Bath dermatitis was first described as early as the 1920s. Today, it is widespread, especially in North America and Central Europe. It is considered a harmless skin disease.
What is bath dermatitis?
Bath dermatitis, also called cercarial dermatitis, is caused by larvae. These multiply primarily in warm months such as June through September. Cercariae prefer water temperatures around 24 degrees. Infestation of humans occurs only by mistake. The actual host of the larvae are ducks and waterfowl. If contact occurs, an initial tingling or mild itching occurs after only 10 minutes. These symptoms are among the primary symptoms. Others follow with repeated contact with the larvae. While bath dermatitis is shown to be unpleasant and bothersome, it is neither dangerous nor does it require special treatment.
Causes
Bath dermatitis is caused by larvae of a sucking worm. This enters water bodies through the worm-infested droppings of waterfowl, mainly ducks. The hatching larvae usually infest snails, which they then use as intermediate hosts, and are released back into shallow water after a few weeks. The new generation of these larvae re-enter through the skin of the ducks, and reproduce. Humans are not considered hosts and are more likely to be affected accidentally. Although the cercariae penetrate the skin of humans, they die within a very short time. On first contact, only mild reactions occur. However, if there is repeated contact with the cercariae, the immune system recognizes them as an invader. The immune system is now activated and the typical symptoms appear. There is no connection with the water quality. The risk of bathing dermatitis, is at waters where very many ducks are present, is greatly increased. For this reason, ducks should not be attracted by feeding, especially in bathing areas.
Symptoms, complaints, and signs
Initial infection with cercariae usually produces no symptoms. Occasionally, reddish wheals form that may be associated with mild itching. In severe cases, pain may be added, which is limited to the area of inflammation and is described by the affected person as throbbing and burning. Allergy sufferers may experience a shock reaction on first contact with the sucker worm larvae. Anaphylactic shock is noticeable by shortness of breath, swelling and other symptoms, which always depend on the extent of the reaction. In the event of a new attack, fever may occur, which manifests itself in the form of palpitations, sweating, fatigue and other typical symptoms. Further wheals and swellings form in the skin area, which are usually sensitive to pressure and scaly in the course of the disease. If the pustules are scratched open, this can lead to infections. Furthermore, bath dermatitis can cause severe discomfort over the entire body. Typical accompanying symptoms are nausea, vomiting and dizziness. Normally, however, bath dermatitis does not cause any major symptoms or discomfort. The condition can be differentiated from other skin diseases based on the noticeable skin lesions and the immediate onset after swimming in a contaminated body of water.
Diagnosis and course
The diagnosis of bath dermatitis is usually made on the basis of the typical symptoms. To substantiate this, a microbiological examination of the water concerned must be carried out. Furthermore, a blood analysis can provide information about a possible bath dermatitis. The blood will then show antibodies against the larvae. Since bath dermatitis is harmless and often does not require any treatment, these costly examinations are usually unnecessary. The course and intensity of bath dermatitis vary from person to person. Thus, very sensitive individuals often react much more strongly. Bath dermatitis can sometimes be accompanied by severe allergic reactions, shock, dizziness, sweating, fever and nausea. However, swollen wheals (3-8 mm in diameter) and severe itching usually occur. The symptoms usually subside after 10 to 20 days, without consequences. The wheals appearing in bath dermatitis, should in no case be scratched open, as this can lead to infection.
Complications
As a rule, no further complications occur with bath dermatitis and the disease is harmless for humans.In most cases, itching occurs in the affected areas due to bath dermatitis. The skin is very red in these areas and has small pimples that resemble a mosquito bite. It is advisable not to scratch these areas on the skin, as this only intensifies the itching and can cause sores and scars. There are formed wheals or papules. However, these are not dangerous and do not need to be treated by a doctor. The itching disappears after a few days, the rest of the symptoms remain on the body for a few weeks and disappear without any particular complications. During bath dermatitis there are no other complaints, however, it is relatively unpleasant on the affected steles and can limit the patient’s everyday life during this period. Scratching the affected areas on the skin can lead to further infections and inflammations. However, in the case of bath dermatitis, these can also be treated relatively well with the help of antibiotics and subside within a few days.
When should you go to the doctor?
Bath dermatitis does not necessarily need to be treated by a doctor. In all cases, the symptoms subside after a few days and do not result in complications. However, if severe itching and swelling occur that have not disappeared after 10 to 20 days at the latest, medical advice is recommended. With severe fever and circulatory problems should go directly to the family doctor. If the frequently occurring wheals open, the wound must be professionally treated. Otherwise, infections and inflammations may occur. People with allergies should go to the doctor if they suspect bath dermatitis. The disease typically occurs after contact with ducks or geese. If symptoms of bath dermatitis occur after bathing in bodies of water where ducks are abundant, it is best to contact your family doctor or a dermatologist. Further medical clarification is recommended especially for allergy sufferers, people with skin diseases, children and pregnant women. After the rash has cleared up, further visits to the doctor are usually not necessary.
Treatment and therapy
As a rule, treatment of bath dermatitis is not necessary. The typical itching can be relieved by soothing ointments or lotions. If it becomes too severe, antihistamines in tablet form as well as ointments containing cortisone help. Treatment with special drugs against parasites or antibiotics, is not necessary, because the larvae die shortly after entering the human body. If severe allergic reactions occur, an emergency physician should be called immediately.
Outlook and prognosis
The prognosis of bath dermatitis can be considered markedly good. It is a temporary phenomenon on the skin that is not normally associated with any permanent adverse effects. The changes on the skin recede within a short time and the normal skin appearance appears. The ingested larvae on the skin cannot cause any harm to the human organism, as they are completely harmless to humans. Medical care or therapy are not necessary for this reason. The usual washing of the body under clean water and with hygienic means or taking a shower is completely sufficient to achieve freedom from symptoms. In rare cases, an allergic reaction of the organism occurs due to the influencing factors. This should be examined by a doctor and, if necessary, treated medically. Even then, the affected person is completely free of symptoms within a few days. If the patient gives in to a possible itching of the skin, open wounds may form. Via these, germs and pathogens have the opportunity to enter the organism. They can trigger secondary diseases that have to be diagnosed and treated individually. In severe cases, the affected person is threatened with blood poisoning. Without medical care, this can lead to a fatal course and thus to the patient’s demise.
Prevention
Prophylaxis against bath dermatitis is extremely difficult. Because cercariae are found primarily in shallow and aquatic plant-rich shoreline areas, these should be avoided if possible. Cercariae prefer warmer water, so swimming in cold water is advisable. Putting on sunscreen also provides mild protection.After swimming, always remove your swimwear and dry off vigorously. This removes possible parasites from the skin. If there are already open spots, do not scratch them. To date, there is no known effective and ecologically justifiable control method against cercariae. In the case of bathing lakes and swimming ponds, feeding ducks should be avoided at all costs. If the domestic pond is also used for bathing, it is recommended to remove dead plant remains and snails with a landing net. This noticeably minimizes the risk of infection.
Aftercare
Bath dermatitis represents an acute and unproblematic skin lesion. Larvae penetrate through the skin and die after a short time. Medical care is unnecessary. It is usually sufficient to dry off well after bathing and apply simple lotions and ointments to the affected areas. There is no need for further aftercare. As a preventive measure, patients should rather stay in deep water. This is because the larvae prefer to live in shallow places near the shore. Complications only arise if contact triggers an allergic reaction. In this case, patients should present themselves to a doctor. The doctor can make a diagnosis on the basis of the antibodies in the blood. A microbiological examination of the water is just as useful, but rarely occurs because of the effort involved. Sometimes wheals remain on the skin surface. Affected persons should not scratch these open, because otherwise an infection may follow. The issue of aftercare is therefore relatively unproblematic in the case of bath dermatitis. Since the disease usually runs completely unproblematic, it is unnecessary outside of an allergic reaction. Affected persons can at most avoid shore areas with the corresponding larvae. Infection is always possible again. Immunity does not build up after a cure.
What you can do yourself
Since the infestation, also known as cercarial dermatitis, can only occur in contaminated waters, prevention is the best means of self-help. Anyone who regularly bathes in lakes, ponds, or slow-moving rivers should take some precautions. The actual hosts of the sucking worm larvae are waterfowl. When bathing, therefore, places with a high concentration of ducks, swans and other waterfowl should be avoided at all costs. Furthermore, the larvae mainly live in the shallower and therefore usually warmer shore areas of the water bodies, which is why these areas should be left quickly when swimming. The use of waterproof sunscreen can prevent the larvae from entering the human body. Thorough showering and vigorous toweling can remove larvae that are still loose on the skin. Bathing clothes should always be changed quickly, as larvae can also be hidden here. If an infestation has occurred, it is not dangerous in itself, but is accompanied by very severe itching, especially if it is a secondary infestation. Antihistamines from the pharmacy, which are available as drops, creams or gels, can help. Patients should not scratch open the very itchy wheals under any circumstances in order to avoid secondary infections. Scratched-on wheals should be disinfected, treated with zinc ointment, and then covered with a band-aid.
